1. Technical Field
The present disclosure relates to cut guides for guiding the resection of a bone to receive a prosthesis component. More particularly, the present disclosure relates to a cut guide for guiding osteotomy of the distal femur to receive a femoral prosthesis having an intercondylar box, e.g., a posterior stabilized femoral prosthesis.
2. Description of the Related Art
Orthopedic prostheses are commonly utilized to repair and/or replace damaged bone and tissue in the human body. For example, a knee prosthesis may include a femoral component which replaces the articular surface of one or both of the natural femoral condyles. Often, the femoral component articulates with a tibial component secured to the proximal end of the patient's tibia so that the knee prosthesis completely replaces the articular surfaces of the natural femur and tibia. A tibial bearing component, which may also be referred to as a tibial insert or a meniscal component is positioned between the femoral prosthesis and the tibia and provides an articular surface which interacts with the femoral component during extension and flexion of the knee.
To prepare the femur and tibia to receive the femoral prosthesis and the tibial prosthesis, respectively, bone cuts or “osteotomies” must be performed to reshape the bones of a joint to receive the prosthetic components. Typically, a single tibial osteotomy is made transverse to the anatomic axis of the tibia. To prepare the femur to receive a femoral prosthesis, five femoral “box cuts” are typically made. The box cuts include osteotomies to form an anterior facet, an anterior chamfer facet, a distal facet, a posterior chamfer facet and a posterior facet on the femur.
Bone cutting instruments are generally referred to as osteotomes and include instruments such as articulating saws, for example, reciprocating or oscillating saws. Cut guides having guide surfaces sized and shaped to guide osteotomes are implemented to facilitate proper location and sizing of bone osteotomies to allow for implantation of prosthesis components.
Femoral prosthesis designs include posterior stabilized prostheses including a spine protruding proximally from the meniscal component and a cam positioned in the intercondylar fossa of the femoral prosthesis component. In posterior stabilized designs, the femoral cam interacts with the tibial spine during flexion of the knee. Posterior stabilized prostheses are typically used in surgical situations in which the posterior cruciate ligament is absent. Posterior stabilized configurations can have varying levels of constraint. An example of a highly constrained design is the Zimmer® NexGen® LCCK which is described together with the surgical technique for implanting the same in the Zimmer® NexGen® LCCK Surgical Technique for Use with LCCK 4-in-1 Instrumentation bearing copyright dates of 2009, 2010 and 2011, the entire disclosure of which is hereby explicitly incorporated by reference herein, a copy of which is included with an Information Disclosure Statement filed in the present application.
To allow for implantation of a posterior stabilized knee prosthesis, intercondylar box cuts must be made in addition to the five femoral “box cuts” described above. Intercondylar box cuts are made from the distal end of the femur toward the proximal end of the femur to remove a portion of the intercondylar fossa which will be replaced by the intercondylar box of the femoral prosthesis so that the intercondylar box of the femoral prosthesis can interact with the tibial spine.